12:21AM

There is nothing unusual going on folks. It’s summertime, and it’s hot. We get into this pattern. And despite the media making it sound like we’re in the midst of another majorly  unusual event, it’s quite common to be hot in the summer. A little Weather 101. But enough editorializing – let’s get to the weather itself. Truthfully, it has not been that brutal. Dew points, though reaching and exceeding 70 in a few locations, have spent much of the time in the 60s during this stretch. Humid? Sure. Not super oppressive. And high temperatures have been in the lower 90s for the most part, with sea breeze cooling near the beaches. Some heat for sure, but not excessive. That said, we may be heading for the worst of it in terms of humidity and heat as surface winds turn more west and southwest Thursday and Friday, after a Wednesday that is similar to the early part of the week – lighter winds with a sea breeze. What has been missing is the haze that we’ve often seen during hot summer patterns. Part of the reason is we are seeing results of more strict laws for emissions. But we also need to get into air that has stagnated and collected pollutants over several days, and we’ve been getting our air from around the edges of the high pressure ridge, with pushes of clean air from eastern Canada and sometimes off the ocean. We will probably see an increase in haze by Thursday and Friday as some of the “dirty” air in stagnating under high pressure in the Midwest makes it into New England.

But what about thunderstorm threats? We have had minimal activity so far in this stretch, with only a few pop up downpours here and there. There will be some changes ahead, and the storm threat should take place something like this:

Wednesday: Focus points will be a weak sea breeze boundary just inland from the NH and eastern MA seacoasts, and also a possible second boundary over areas inland from the South Coast in southern MA and parts of RI created by a more southerly wind there. Also a trigger from a weak disturbance passing north of the region may enhance development. Not looking for widespread activity,  just isolated to widely scattered, with no real threat of severe storms.

Thursday: In the heat and humidity a pop up storm is possible anywhere during the afternoon and evening, but a disturbance coming along from the west northwest may develop a cluster or line of storms somewhere in western New England that may then cut across parts of MA and RI (favoring areas southwest to south of Boston), late afternoon or early evening.

Friday: Isolated storms may pop up in the heat, but more stable air aloft may limit development. Will keep an eye on this in case it is less stable than I currently expect.

Saturday: This day carries the most potential with the arrival of a cold front into a hot, humid airmass, along with much greater instability and parameters for possible severe weather. However, it will be all in the timing, and will also depend on whether or not any secondary trough lines form (little disturbances that often accompany passing fronts). These troughs can fire storms earlier than expected, but sometimes will limit later development. There is also a chance that the cold front itself arrives sooner than the computer models currently show. This would also  limit severe storm development, and end the threat earlier. There is enough potential and enough uncertainty to stress that this potential weather situation needs to be closely monitored.

Since I am leaning toward a quicker frontal passage, I will be optimistic for Sunday and the start of next week, with less heat and humidity and generally fair weather at least Sunday and Monday. A disturbance may bring unsettled weather to the region Tuesday, but this is way out in the future and timing may change.

Updated forecast for southeastern New England…

TODAY: Partly cloudy. Isolated to widely scattered afternoon showers/thunderstorms. Highs 90-95 except upper 70s to 80s coastal areas.  Wind variable to S 5-15 MPH with coastal sea breezes.

TONIGHT: Partly cloudy. Any isolated showers end early. Lows upper 60s to middle 70s. Wind S to SW up to 10 MPH.

THURSDAY: Partly cloudy and hazy. Isolated afternoon thunderstorms and a chance of a cluster of storms mainly west and south of Boston late afternoon or early evening hours. Highs 91-96 except 80s to around 90 coastal areas that face south. Wind SW 10-20 MPH.

FRIDAY: Mostly sunny and hazy. Isolated afternoon thunderstorms. Highs 94-99 except cooler in a few areas of the South Coast through Cape Cod. Wind SW to W 10-20 MPH.

SATURDAY: Variably cloudy.  Thunderstorms, some strong. Low 74. High 91.

SUNDAY: Partly cloudy. Low 63. High 83.

MONDAY: Partly cloudy. Low 62. High 82.

TUESDAY: Increasing clouds. PM showers. Low 63. High 80.

12:39AM

A large area of high pressure will continue to drift westward over the eastern USA. Here in southern New England we will be on the northeastern side of this ridge, and though it’s a generally hot pattern for most of the region, it does allow for some natural air conditioning via a sea breeze, and this will be possible through midweek, possibly even enhanced a little by a weak back-door cold front coming into some areas today. By later in the week, a more prominent west to southwest wind will limit the ocean cooling to the South Coast and Cape Cod, and while this is ongoing, a trough of low pressure and associated cold front trying to press southeastward out of Canada will provide  energy and focus for a better chance of thunderstorms starting late Thursday but especially Friday and Saturday. The timing of the front is uncertain this far out, so it is difficult to pin-point the coverage and timing of storms. There is some potential for strong to severe storms, regardless. Wording will be vague for now and will be fine-tuned as the potential event draws closer. By late in the weekend, provided the front does not get hung up, we should be treated to somewhat cooler and less humid air.

Updated forecast for southeastern New England (southern NH, eastern MA, and RI)…

TODAY: Mostly to partly sunny. Isolated to scattered showers and thunderstorms possible mainly interior eastern MA, southern NH, and northern RI from mid afternoon to sunset. Highs 90-95 but 80s beaches possibly falling to the upper 70s NH Coast to Cape Cod late. Wind variable to N 5-15 MPH shifting more to the NE from southeastern NH into eastern MA during the afternoon.

TONIGHT: Partly to mostly clear. Lows upper 60s to lower 70s. Wind variable 5-10 MPH.

WEDNESDAY: Mostly to partly sunny. Isolated to scattered afternoon thunderstorms possible, favoring southern NH and interior southeastern MA to northern RI. Highs 90-95 inland areas, 80s beaches. Wind variable 5-15 MPH with coastal sea breezes developing.

THURSDAY: Partly cloudy. Isolated to scattered PM thunderstorms. Low 71. High 92.

FRIDAY: Partly cloudy. Scattered PM and evening thunderstorms. Low 73. High 94.

SATURDAY: Variably cloudy. Scattered showers/thunderstorms. Low 70. High 89.

SUNDAY: Partly cloudy. Low 64. High 82.

MONDAY: Mostly sunny. Low 62. High 84.

10:15PM

Upper level high pressure will be entered just southwest of New England to start the week but will retrograde further west with time, allowing the jet stream to sink a little further southward over the region by the end of the week, along with some disturbances moving along it. A weather front may get close and sneak down part of the coast on  Tuesday and will again make an appearance nearby about Friday, finally getting pushed southward with a couple of secondary trough lines or weak fronts traversing the region by the weekend.

The overall story for much of the week will be the heat and humidity dominating the region. But that series of fronts by the end of the week may deliver a shot of less humid, less hot air by later in the weekend.

Forecast for southeastern New England…

OVERNIGHT: Clouds depart the South Coast, a few low clouds and fog patches may form, otherwise mostly clear. Humid. Lows middle 60s to lower 70s. Wind light variable.

MONDAY: Mostly sunny to partly cloudy. Slight chance of an isolated thunderstorm late day or early evening mainly northern MA and southern NH. Humid. Highs lower 80s South Coast and Cape Cod to lower 90s most locations. Wind variable to NW 5-15 MPH.

MONDAY NIGHT: Partly cloudy to mostly clear. Humid. Lows middle 60s to lower 70s. Wind light NW to N

TUESDAY: Mostly sunny to partly cloudy. Chance of a few showers and thunderstorms mainly interior southern NH, east central MA, and northern RI mid afternoon through early evening. Humid. Highs middle 80s to lower 90s, but may cool back through the 80s to the upper 70s coastal areas especially southern NH to eastern MA coastal areas later in the day. Wind N 5-15 MPH may turn more NE in NH and MA coastal areas.

WEDNESDAY: Mostly sunny to partly cloudy. Isolated PM thunderstorms favoring southern NH and northeastern MA. Low 69. High 91.

THURSDAY: Partly cloudy. Isolated to scattered PM thunderstorms favoring southern NH, northeastern and east central MA. Low 70. High 92.

FRIDAY: Partly sunny. Scattered thunderstorms. Low 72. High 90.

SATURDAY: Partly cloudy. Isolated showers and thunderstorms. Low 68. High 88.

SUNDAY: Mostly sunny. Low 64. High 82.

10:08AM

It’s time for the heat again, starting today in some areas and in pretty much all areas Monday through Thursday, hanging on in many Friday, before easing slightly next weekend. That’s a capsule of the coming week plus. A full discussion will follow later with The Week Ahead post but for now here is an updated forecast for southeastern New England…

TODAY: Mostly sunny to partly cloudy. Isolated thunderstorms possible especially late afternoon or early evening but most areas rain-free. Humidity rising. Highs in the 80s, may hold in the 70s some immediate coastal areas and may approach 90 interior valleys. Wind variable 5-15 MPH.

TONIGHT: Partly cloudy to mostly clear. A few patches of fog. Muggy. Lows 65-70. Wind light variable.

MONDAY: Mostly sunny to partly cloudy. Slight chance of isolated thunderstorms late day. Highs around 90, cooler some beaches. Wind variable to NW 5-15 MPH.

TUESDAY THROUGH THURSDAY: Mostly sunny to partly cloudy each with a risk of a few isolated thunderstorms mainly late afternoons and early evenings. Lows 64-74, warmest urban areas. Highs 84-94, coolest some coastal areas with most areas 90+.

FRIDAY: Partly sunny. Thunderstorms late. Low 70. High 90.

SATURDAY: Partly cloudy. Showers early. Low 66. High 88.

5:41PM

A cold front is lazily drifting across southeastern New England and won’t even clear Cape Cod before stalling and washing out during the next couple days. The lingering boundary will help initiate some shower activity, but the best chance for this will be Friday as a disturbance also crosses the region. Activity should diminish though is still possible during the weekend.

A repeat of the retrograding ridge pattern (high pressure moving westward from the western Atlantic) will bring a return to hot weather for much of next week.

Updated forecast for southeastern New England (eastern MA, southern NH, and RI)…

THIS EVENING (THROUGH SUNSET): Filtered sunshine most areas, but some heavier clouds and isolated to scattered showers and possible thunderstorms (especially Metro West and Merrimack Valley). Temperatures ranging from near 70 coast to near 80 inland, but cooler in areas that showers occur. Wind S to SW in eastern areas, NW to N further to the west, 5-15 MPH.

OVERNIGHT: Mostly cloudy. Lows in the 60s. Wind N up to 10 MPH except variable in coastal areas.

FRIDAY: Mostly cloudy. Episodes of showers, especially late morning and afternoon. Slight chance of a thunderstorm. Highs in the 70s, coolest coast. Wind NE to E 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Patchy fog. Chance of showers. Lows in the 60s. Wind light SE.

SATURDAY: Mostly cloudy to partly sunny, except more sun possible north and west of Boston in the afternoon. Chance of showers and possibly a thunderstorm, favoring areas from the Mass Pike southward. Highs middle 70s to middle 80s, coolest coastal areas. Wind SE to S 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Patchy fog. Lows in the 60s. Wind S 5-15 MPH.

SUNDAY: Partly sunny. Isolated showers and thunderstorms especially south of Boston. Highs in the 80s. Wind S 10-20 MPH.

MONDAY-THURSDAY: Partly cloudy. Isolated thunderstorms possible each afternoon. Lows 65-75. Highs 85-95, coolest South Coast and Cape Cod.

11:48PM

If you regularly look at the computer models, you’ll know right away which one I am leaning toward. With a warm front moving through the region today, a cold front sliding into the region then slowing down just offshore Thursday and Friday, and a probable cut off low pressure area forming over the region early in the weekend, it looks like an unsettled time continuing for southeastern New England during the next several days. Optimistically, better weather should be expected by late in the weekend or more likely early next week as a ridge of high pressure in the western Atlantic starts to build westward into the Northeast, much like what happened last week, resulting in the heat. Before that, expect several period of showers and thunderstorms.

Updated forecast for southeastern New England…

OVERNIGHT: Mostly cloudy. Areas of fog Cape Cod, Islands, southeastern and east coastal MA. Lows in the 60s. Wind light E to SE.

WEDNESDAY: Mostly cloudy morning with patchy rain moving south to north across the region. Variably cloudy afternoon with a stray shower or thunderstorm possible interior MA and south central NH. Highs 70s coast, 80s inland. Wind SE shifting to S increasing to 10-20 MPH.

WEDNESDAY NIGHT: Mostly cloudy. Showers and thunderstorms moving in from west to east but weakening as they cross the region. Lows 65-70. Wind SW 5-15 MPH.

THURSDAY: Variably cloudy. Scattered showers and thunderstorms. Highs 75-85, coolest South Coast, warmest interior MA and NH. Wind variable 5-15 MPH.

FRIDAY: Mostly cloudy. Showers and possibly a thunderstorm in the morning becoming less numerous in the afternoon. Low 66. High 74.

SATURDAY: Mostly cloudy. Scattered showers. Low 62. High 75.

SUNDAY: Partly cloudy. Isolated showers. Low 64. High 82.

MONDAY: Sunny. Low 65. High 88.

TUESDAY: Sunny. Low 68. High 92.

7:39AM

We became a meso-scale weather lab experiment on Monday as cool outflow air from thunderstorms exiting Maine into the Atlantic pushed southward as a back-door frontal boundary and moved into southern NH and much of eastern MA, popping some showers and thunderstorms in the process. This boundary cooled coastal areas off from around 80 to near 70, 60s in some cases, while areas well southwest of Boston remained very warm. This boundary which has now cooled off most of the region and even notched-down the humidity (though it is still technically humid) will hang around the region and fall apart today, being only a minor focus for development of showers. We’ll have to wait for another boundary, a warm front, to push through the region early Wednesday, with showers and thunderstorms, introducing very muggy air back to the region from mid into late week. Additional showers/storms are expected Thursday-Friday as a cold front moves into the region from the west and slows down. Its too early to tell how soon this will get out of here, but there is optimism for at least part of the weekend being better.

Updated forecast for southeastern New England…

TODAY: Mostly cloudy to partly sunny. Isolated showers. Highs 70 coast to 80 far inland. Wind light E becoming variable.

TONIGHT: Mostly cloudy. Patchy fog. Showers mainly south and west of Boston late. Lows in the 60s. Wind light variable to SE.

WEDNESDAY: Variably cloudy. Episodes of showers and thunderstorms. Highs upper 70s to middle 80s. Wind S to SW 10-20 MPH.

THURSDAY: Showers and thunderstorms likely. Low 66. High 85.

FRIDAY: Showers and thunderstorms possible. Low 68. High 82.

SATURDAY & SUNDAY: Isolated showers and thunderstorms. Lows 60-68. Highs 78-88.

MONDAY: Sunny. Low 66. High 88.

9:36PM

The heatwave that impacted parts of the region from as early as Wednesday through Sunday is done, but the humid pattern is not going anywhere during the coming week. Though a weak trough will dominate, this trough sits between a ridge to the west and a rebuilding ridge in the western Atlantic, and with no real push of dry air available from Canada, the humidity level will remain rather high right through the next 7 days. It won’t be as hot because of the lack of ridging and limited sunshine through at least the end of the work week. By sometime next weekend, another retrogression or westward movement of high pressure from the Atlantic may heat the region up again. Some signs point to another potential heatwave resulting but not until sometime the following week. We’ll also be eyeing an early-season system in the tropics for development and eventual track.

In the mean time, the updated forecast for southeastern New England goes something like this…

OVERNIGHT: Variably cloudy. Patchy fog valley and swampy areas. Humid. Lows in the 60s to lower 70s, warmest in urban centers. Wind light variable.

MONDAY: Variably cloudy. Showers and thunderstorms developing mid to late afternoon. Humid. Highs 80-85 except 70s South Coast. Wind S to SW 10-15 MPH, higher gusts.

MONDAY NIGHT: Mostly cloudy. Showers and thunderstorms likely early then diminishing. Patchy fog redeveloping. Muggy. Wind light SW to W.

TUESDAY: Partly sunny. Slight chance of afternoon showers or thunderstorms. Humid. Highs upper 70s to middle 80s. Wind W 5-15 MPH.

WEDNESDAY: Partly sunny. Scattered showers/thunderstorms. Low 66. High 84.

THURSDAY: Variably cloudy. Scattered showers/thunderstorms. Low 67. High 83.

FRIDAY: Mostly cloudy. Scattered showers/thunderstorms. Low 68. High 81.

SATURDAY: Variably cloudy. Scattered showers/thunderstorms. Low 66. High 83.

SUNDAY: Partly cloudy. Low 67. High 88.

11:44AM

The high pressure ridge that pushed most of the storms back to the west of the WHW forecast area of southern NH, eastern MA, and RI, will start to flatten this weekend, still keeping us in the ongoing heatwave, but allowing a slightly greater risk that a few showers and storms could get into the area. The ridge will weaken and retrograde further to the west during the coming week, as a new ridge re-builds in the western Atlantic. This will leave our area in a weak area of troughing that will bring increase shower and thunderstorm activity, less heat (80s instead of 90s), but continued humidity.

Updated forecast for southeastern New England…

TODAY: Partly cloudy. Isolated late day thunderstorms. Highs 92-97 except 80s to around 90  South Coast, Cape Cod, and Islands. Wind W 10-20 MPH.

TONIGHT: Partly cloudy. Isolated showers or thunderstorms early. Lows upper 60s to middle 70s. Wind W 5-15 MPH.

SUNDAY: Partly sunny. Scattered afternoon thunderstorms. Highs 90-95 except 80s South Coast, Cape Cod, and Islands. Wind W to SW 10-20 MPH.

MONDAY THROUGH FRIDAY: Daily episodes of scattered showers and thunderstorms. Lows 65-72. Highs in the 80s.

7:31AM

Happy Birthday USA!

This is just a carry-forward of yesterday’s forecast, getting rid of old info. Discussion on previous entry is the same. Have a safe and happy 4th of July everyone!

TODAY – INDEPENDENCE DAY: Partly cloudy. Slight chance of isolated afternoon to early evening thunderstorms north and west of  Boston. Humid. Highs from around 80 South Coast to around 90 elsewhere. Wind SW 5-15 MPH.

TONIGHT: Partly cloudy. Muggy. Lows upper 60s to lower 70s. Wind SW up to 10 MPH.

FRIDAY: Mostly sunny. Humid. Highs upper 80s to lower 90s, cooler South Coast. Wind SW to W 5-15 MPH.

SATURDAY & SUNDAY: Isolated PM thunderstorms. Lows 65-75. Highs 85-95.

MONDAY & TUESDAY: Scattered PM thunderstorms. Lows 65-75. Highs 85-95.

9:21AM

The outline from a few days ago is basically the same. Retrogression of high pressure from the western Atlantic will continue and eventually merge with high pressure from over the southern USA to form a large flat ridge of  high pressure, creating a hot weather pattern that will last well into next week. A little house-cleaning details are being taken care of today before this really gets underway. The back-door cold front that cooled off and in some cases fogged up parts of southern NH and eastern MA is heading back northeastward as a warm front and that cooler maritime air will be a distant memory in a short time. The thunderstorm threat is also diminishing, though we cannot rule out pop up storms from time to time in this pattern. For the next few days, the most likely place to see them would be across interior MA and southern NH in the late afternoon to early evening. Plan on mainly rain-free, very warm to hot, humid conditions. The most cloud cover will probably exist today, as the high pressure ridge continues to push the tropical moisture belt that had been over the region back to the west.

Updated forecast for southeastern New  England (southern NH, eastern MA, and RI)…

THIS AFTERNOON: Variably cloudy. Isolated showers and thunderstorms. Highs upper 70s South Coast to 80s elsewhere. Humid. Wind SW 10-15 MPH, gusting 20-25 MPH.

TONIGHT: Partly cloudy. Muggy. Lows in the 60s. Wind SW 5-15 MPH.

THURSDAY – INDEPENDENCE DAY: Partly cloudy. Slight chance of isolated afternoon to early evening thunderstorms north and west of  Boston. Humid. Highs from around 80 South Coast to around 90 elsewhere. Wind SW 5-15 MPH.

THURSDAY NIGHT: Partly cloudy. Muggy. Lows upper 60s to lower 70s. Wind SW up to 10 MPH.

FRIDAY: Mostly sunny. Humid. Highs upper 80s to lower 90s, cooler South Coast. Wind SW to W 5-15 MPH.

SATURDAY & SUNDAY: Isolated PM thunderstorms. Lows 65-75. Highs 85-95.

MONDAY & TUESDAY: Scattered PM thunderstorms. Lows 65-75. Highs 85-95.

12:51AM

Before I update the coming weather, a quick look back at the surprise “severe weather outbreak” of Monday. I put it in quotes, because it was not a severe outbreak in the classic sense. What these storms were made of was low level wind sheer. The storm tops were not very high. They were not typical storms, producing large hail and widespread damaging winds. Lightning was sparse at best. These storms were more like what you might see in a land-falling tropical storm, producing relatively weak spin ups (very brief and weak tornadoes), still capable of producing damage, however.

The set-up that caused this will still exist today (Tuesday), and though storms and showers may be a little less numerous overall, we will still have to watch for the possibility of isolated flooding downpours and isolated tornadoes and/or micro bursts in rapidly-developing tropical showers and storms. A very warm and humid tropical air flow will provide plenty of fuel for this.

As we have been discussing, the retrogression (westward movement) of the ridge of high pressure in the western Atlantic Ocean is underway and will continue through this week. After today, it means a decrease in thunderstorm activity, coverage-wise, though the threat will still exist at times, mainly in isolated form. It also means an increase in heat, and a continuation of humidity. This will include the Independence Day holiday and through the extended weekend following it. Anybody with outdoor plans should take precautions to stay protected from the sun, stay hydrated, and watch for any thunderstorms that develop or move into the region.

Updated forecast for southeastern New England (RI, eastern MA, southern NH)…

TODAY: Mostly cloudy with scattered to numerous showers and embedded thunderstorms. Isolated storms may produce damaging wind and local flash flooding. Very humid. Highs middle 70s South Coast to 80-85 interior areas. Wind SW 10-20 MPH.

TONIGHT: Mostly cloudy. Areas of fog. Lingering showers becoming isolated then ending. Very humid. Lows middle 60s to 70. Wind SW 5-15 MPH.

WEDNESDAY: Mostly cloudy with patchy fog early, then partly sunny. Isolated to scattered thunderstorms during the afternoon. Humid. Highs upper 70s to middle 80s. Wind SW 5-15 MPH.

THURSDAY – INDEPENDENCE DAY: Partly cloudy. Isolated thunderstorms mainly late day and early evening favoring far northern MA and southern NH. Low 70. High 87.

FRIDAY: Partly cloudy. Isolated late-day thunderstorms. Low 70. High 90.

SATURDAY: Mostly sunny. Isolated late-day thunderstorms. Low 71. High 91.

SUNDAY: Mostly sunny. Isolated late-day thunderstorms. Low 70. High 90.

MONDAY: Sunny. Low 69. High 88.

2:08AM

With no major changes to the forecast, this is basically a re-issue of the last blog with tweaks for timing and a few added details, and of course updated for the time period.

2:30AM

Here is my best guess at the weather pattern and resultant day-by-day weather through the first week of July, including the Independence Day holiday (and 2 weekends either side of it).

The battle between a high pressure ridge over the western Atlantic Ocean and low pressure trough centered near the Great Lakes will continue this final weekend of June and the first 2 days of July, with a retrograding ridge eventually being the victor. The result will be mild to warm air, high humidity, and episodes of scattered showers and thunderstorms through Monday, with less shower activity but still a shower and storm threat lingering Tuesday. Many areas will see lengthy stretches with no rain, but any tropical showers and storms may produce drenching downpours. At this point, I expect the day with the most numerous shower activity in southeastern New England to be Monday.

High pressure will continue to drift westward over the western  Atlantic and US East Coast through much of next week, only weakening a little as disturbances try to ride over the top of it from the west by the first weekend of July. The overall pattern for this area will become hotter and continued humid. Shower and thunderstorm activity will be isolated, increasing to scattered in some areas with passing disturbances later in the period.

Updated forecast for southeastern New England (RI, eastern MA, southern NH)…

TODAY: Mostly cloudy morning with isolated to scattered showers. Partly sunny afternoon with isolated to scattered showers and thunderstorms. Humid. Highs middle 70s to lower 80s. Wind S 5-15 MPH, up to 20 MPH some coastal areas.

TONIGHT: Variably cloudy. Isolated showers/thunderstorms early. Patchy fog overnight. Muggy. Lows in the 60s. Wind S under 10 MPH.

SUNDAY: Variably cloudy. Isolated to scattered showers and thunderstorms redeveloping. Humid. Highs upper 70s to lower 80s. Wind S to SW 10-20 MPH.

MONDAY: Mostly cloudy. Scattered to numerous showers/thunderstorms. Low 66. High 77.

TUESDAY: Partly cloudy. Isolated to scattered late-day showers/thunderstorms. Low 67. High 83.

WEDNESDAY: Partly cloudy. Isolated late-day thunderstorms. Low 68. High 84.

THURSDAY: Partly cloudy. Isolated late-day thunderstorms. Low 68. High 86.

FRIDAY: Partly cloudy. Isolated late-day thunderstorms. Low 69. High 88.

SATURDAY: Partly cloudy. Isolated to scattered afternoon thunderstorms. Low 70. High 90.

SUNDAY: Partly sunny. Scattered showers/thunderstorms. Low 70. High 88.

9:31AM

The battle will be on between a Great Lakes trough and a western Atlantic ridge for several days. The ridge will eventually win out for much of southern New England, but enough of a battle from the trough will be given to result in a continued threat of showers and thunderstorms for several days. The thing is, there will be high variability in rain coverage. Widespread wet times will be few, scattered to isolated coverage will be much more common.

First, we have a wedge of cooler air that came southwestward last evening behind a disturbance and pseudo-back-door cold front. It has left low clouds and areas of fog in much of the region and it will take a while to burn that away today. During this time, a band of heavier clouds just to the south as indicating the position of a boundary between this cooler air and the return push of warm and humid air from the south. This boundary will be a focus for generation of some rain as we go through today and this evening, but there is some question as to exactly how much rain will generate and fall in the region. I’m banking on less than some have advertised. So today may feature more “bark” than “bite” in terms of clouds and rainfall. By later tonight, we will see a heavier band of rain and embedded thunderstorms move in from the west with a trough line swinging out from a low pressure center passing northwest of New England. The axis of this heavy rain should time through southern New England between midnight and mid morning Friday. The remainder of Friday may not feature all that much in the way of widespread rain, but we’ll still have to look for isolated to scattered showers and thunderstorms. This boundary will be close to the coast or maybe just offshore, and along with a more established southerly flow of tropical air, showers and thunderstorms will be possible any time during the weekend, favoring Saturday over Sunday, but it’s quite possible that long rain-free periods will take place as well.

Retrogression (westward-movement) of the ridge of high pressure in the western Atlantic will take place during the first half of next week, putting the region into hotter conditions, still humid, and still with a threat of showers and storms, but more isolated with time as the axis of most likely activity shifts to the west.

Tomorrow, a special 10-day forecast looking out through the entire first week of July.

Updated forecast for southeastern New England…

TODAY: Low clouds and areas of fog through the morning. Remaining mostly cloudy midday through afternoon however breaks of sun and isolated showers both possible. Highs in the 70s, upper 60s few coastal points. Wind E 5-15 MPH.

TONIGHT: Mostly cloudy. Areas of light rain possible in the evening, favoring southern NH. Widespread showers/thunderstorms arriving west to east mainly after midnight. Lows in the 60s. Wind E to SE 5-15 MPH.

FRIDAY: Mostly cloudy with showers and embedded thunderstorms ending west to east in the morning. Partly sunny with isolated to scattered passing showers and thunderstorms in the afternoon. Highs 80-85 except 70s some coastal areas. Wind SE to S 10-20 MPH.

SATURDAY & SUNDAY: Variably cloudy. Episodes of scattered showers/thunderstorms. Lows 65-70. Highs 75-85, coolest south-facing coastal areas.

MONDAY-WEDNESDAY: Partly cloudy. Daily risk of isolated to scattered thunderstorms. Lows 66-72. Highs 77-90, coolest south-facing coastal areas.